A beginner's map of the Moon
Five landmarks you can find with a pair of binoculars, and why a half Moon beats a full one.
The Moon is the one object in the night sky that rewards you whatever you look at it with. Your eyes show its light and dark patches, binoculars reveal craters, and a small telescope turns it into a landscape you could lose an evening in.
Why a half Moon beats a full one
It sounds backwards, but a full Moon is the worst time to look for craters. With sunlight hitting the surface straight on there are no shadows, and everything looks flat. Look instead along the terminator, the line between lunar day and night, where low sunlight throws long shadows and craters jump out in relief. The few days around first quarter are ideal.
Five landmarks to find
- 01
Sea of Tranquility
A smooth, dark plain of ancient lava, and the place where Apollo 11 landed in July 1969.
- 02
Sea of Showers
Mare Imbrium, one of the largest dark plains, filling a huge basin blasted out by an ancient impact.
- 03
Copernicus
A crisp, terraced crater about 93 kilometers wide, often called the Monarch of the Moon.
- 04
Tycho
A young crater in the southern highlands whose bright rays splash across the Moon. Unlike most craters, it looks best near full Moon.
- 05
The Apennine Mountains
A long arc of peaks on the edge of the Sea of Showers that catches the sunlight dramatically a day or so after first quarter.
The face that never changes
The Moon spins exactly once for every trip around Earth, so the same side always faces us. A gentle wobble called libration lets us peek at a little more over time, about 59 percent of the surface in all. The map you learn tonight will still be right in fifty years.
Start with the dark seas, which are easy to spot even without optics, then work your way to the craters along their edges. Within a few nights the Moon stops being a light in the sky and starts being a place.
Never miss a night worth staying up for.
One email a month with what is coming up in the sky.
